Along with the continuous progress of radio technology, a large number of various radio serves have emerged. However, spectrum resources on which radio services depend are limited; facing the increasing demand from people on bandwidth, spectrum resources show an extremely strained situation, while in a conventional fixed spectrum allocation mode, the utilization rate of spectrum resources is not high. Improving the utilization rate of spectrum resources becomes a main means for solving a contradiction between increased demand and limited resources, which is also a core idea of CR technology.
The improvement of the spectrum utilization rate can be realized by waiting for an opportunity to occupy the spectrum resources (such as TV White Spaces (TVWS)) which are temporarily unused by authorized services in other frequency bands. The spectrum resources which are temporarily unused by other systems are borrowed to share part of wireless communication services with a spectrum-strained cell, which undoubtedly can ease the spectrum-strained situation of the wireless communication service of the cell; however, if the borrowing from a subsystem is not limited, malicious spectrum occupation may probably occur. For example, when a plurality of systems occupy a certain section of spectrum resources which are temporarily unused by an authorized service in a shared way, each system hopes to acquire borrowed spectrum resources as much as possible, thus malicious application for occupation is transmitted; and if a spectrum borrowing rule is not proposed for different interest regions in a single system, malicious application for occupation of borrowed spectrum resources may also occur; in this way, part of systems or cells, even when their spectrum resources are not strained, may occupy relatively more borrowed spectrum resources, and the systems or cells with strained spectrum are likely to obtain rare borrowed spectrum resources.